Tank



pri 241, 1945. M, SHANKMAN 2,374,240

TANK

Filed Oct. 30, 1942 5 Sheets-Sheet 2 FiEI EI l 3mm MaI-tin .Enhankman pi24, w45. M. SHANKMAN 2,374,240

TANK v Filed oct. 3o, 1942 3 sheets-sheet 5 Martin Shan-1km an @www hemdApr. :mp4s:

Martin snankman, nunungio, N. Y.

, Application october so, 1942, sei-lama. 463,819

6 Claims.

(Cl. 18th-9.1)

(Granted under :ne et of March s, lass, u

amended April so, 192s: 31o o. o. 151i The invention described hereinmay be manufactured and used by or for the Government for governmentalpurposes, without the payment to me of any royalty thereon.

'Ihis invention relates to amphibious tanks, such as would be used byassault troops attempting to establish a bea-ch head.

When assault troops try to establish a beach' head, they approach theenemy-held beach in force from surface vessels which come in as close aspracticable to the beach. There they disembark in landing boats of somekind and make for shore. Such boats should aiord the troops protectionagainst light machine gun and rie fire, and should permit them to movein fast.

It is the object; of this invention to provide an amphibian tank capableof launching from a troop carrier for the approach to an enemy-heldbeach. The tank is preferably propelled through the water by its track,which can be lengthened for the purpose. The tank carries aturretmounted machine gun.

The tank is designed to carry a driver and a gunner, and is well adaptedfor use in squads of twelve to a squad. Weight of a tank would notexceed three tons, and would preferably be held closer to two tons.

The specific nature of the invention as Well as other objects andadvantages thereof will clearly appear from a description of a preferredembodiment as shown in the accompanying drawings in which:

Fig. 1 of the drawings is an elevational view of a tank of the inventionwith its tracks positioned for land travel.

Fig. 2 is a view similar to Fig. 1 showing the tank with its trackspositioned for water travel.

Fig. 3 is a view in perspective of the mechanism to lower and raise thetrack.

Fig. 4 is a side elevational view of the tank interior, the shell beingin section to show the arrangement inside the tank.

Fig. 5 is a top view of the tank.

Fig. 6 is a top View, with the shell in section to show the interior.

Fig. 7 is a detail view of the hydraulic power' system used to raise andlower the tank with respect to a portion of the track.

Referring to the drawings in detail, especially to Figs. 1 and 2, a bodyor hull 2 is shown provided wlth a turret 4 at its forward end throughwhich a machine gun 6 projects. The tank is carried and propelled by anendless track 8 which runs on a drive sprocket I0, lower idler wheelsl2, end wheel I4, and upper idler wheels or rollers I6.

As can better bev seen in Fig. 3, lower idler wheels l2 are carried ontrucks I8. Each of trucks I8 is mounted on a piston rod 2B, on which ismounted a piston 22 which moves in a double acting cylinder '24.Cylinders 2| are mounted in a projecting compartment 25 on the side ofthe tank. End wheels i4 are moved up and down by the piston, not shown,of cylinder 26 through bell crank 21. Cylinder 26 may be single ordouble acting. If single acting, the power will be applied to move thewheels downward to take up the slack when lengthening the track forwater travel.

Fig. l`i shows the tank interior. As can be seen in this figure andFigs. 5 and 6. the tank body consists of a substantially sphericalforward portion 28 made, preferably, of about half-inch armor plate andwelded to a generally rectangular portion 30 which is also armor platebut of a thinner section, such as quarter inch material. The portion 28is provided with vision slits 32. Surmounting the spherical portion andforming ra part of it is the turret 4, in which gun 6 is mounted bymeans of a ball and socket joint indicated generally by 34. A slit 36 inthe forward part of the turret provides visio-n for the gunner. Theturret may if desired be made of a thinner section than the rest of thespherical portion.

The rectangular portion 3B of the body has a trap door 38 to permitentering and leaving the tank. A ventilator unit fill is also providedin the upper surface. Any suitable power plant 42 is mounted in the rearpart of the tank. A heat exchanger M, such as a radiator for an internalcombustion engine, may be disposed behind a substantially bullet-proofgrille 46. The exhaust` pipe 68 can be passed through a small openingAin the upper surface of the body. Fuel for engine 42 may be carried intanks 52. The connections between fuel tanks and engine are not shown,nor are throttle controls and the like, inasmuch as these areconventional and form' in themselves no part of this invention.

A drive shaft 54 transmits power to a controlled differential 56 througha power take-off SBand a shaft B0. Steering may be by means of thecontrolled differential or by means of track clutches and brakes, notshown, although the controlled differential will be recognized aspreferred. Either method is conventional and need not be detailed here.

A drivers seat B2 is shown at the left of the shaft 60, and a gunnersseat `(il is shown as wheels I2 and I4. This nuid may be supplied by apump 68 connected to be driven by motor 42 through shaft d and powertake-off B. The pump may of course be a conventional pump adapted to thetype of iluid used in the system, which may be pneumatic or hydraulic,by way of example. A pneumatic system has the advantage ot providingcushioning means in addition to the springing action in trucks i8, and ahydraulic system has the advantage of more positive response.

Various conduits connect the pump 66 to cylinders 24 and 2 8 through avalve 12. The details orthis'system are best shown in Fig. 7. A conduit14 connects the pump discharge with the middle of the valve cylinder, inwhich is mounted a slide 16 to cover and uncover ports 'I8 and 60. Port'I8 leads to the upper side of pistons 22 in cylinders 24, to the lowerside of the pistons in cylinders 26, by means of` conduits 82, 84, and86as shown. Port 80 leads to the lower face of the pistons in cylinders 24and to the upper'iace of the pistons in cylinders 26 through conduits88, 00, 82, and 94. The ends of the valve cylinder are connected to thepump suction through conduit 96 and a reservoir 88. A handle |00 permitsthe manipulation of slide 16.

Operation- If the tank is in condition for land travel, and it isdesired to prepare it for water travel, handle |00 is pushed inwardtoward the valve body. Slide 16 thereupon uncovers ports 16 and 60,exposing the lower sides of pistons 22 and the upper faces of thepistons in cylinders 26 to the high pressure side, or discharge, ofpumpv 6l through port 60. The upper ends of cylinders 24 and the lowerends of cylinders 26 are connected to the suction, or low-pressure, sideof the pump through port 76. Cylinders 24 raise the idler wheels I2, andcylinders 26 lower the end wheels I4, lengthening the lower portion ofthe track to the condition shown in Fig; 2. The track will then propelthe tank through the water.

If then it is desired to prepare the tank again for land travel, handle|00 is pulled outward from the valve cylinder, uncovering ports 18 and80 and zonnecting, through port 18, the upper ends of :ylinders 24 andthe lower ends of cylinders 26 with the pump discharge; the lower endsof cylinlers 24 and the upper ends of cylinders 26 are hereby connectedto the-pump discharge through ort 60. The lower portion of the track istherey lowered with relation to the tank, putting the ank in thecondition shown in Fig. 1.

I claim:

1. In a track-laying vehicle, a drive motor, racks driven b y saidmotor, idlers in engagement vith the inside of the tracks and operableto raise r lower the vehicle body'with relation to the racks, idlersnormally above and ahead of the ither idlers, and means for lowering thelast-inenioned idlers to bring them substantially in line with the otheridlers when the vehicle body` is )wered relative to the tracks to takeup slack in he tracks and incidentally lengthen its traction ase.

2. In a track-laying vehicle, a drive :notons sprocket driven by saidmotor, a rockably mounted idler spaced from the sprocket andsubstantially in line therewith, a track around the sprocket and saididler, other idlers in engagement with the inside of the track betweenthe sprocket and the rockable idler, means for raising the intermediateidlers to diminish the distance between the track 'and thefbottom of thevehicle body and incidentally cause slack in the track, and means forrocking the rockable idler to take up the slack and incidentallylengthen the traction base oi' the track.

3. In an amphibious track-laying vehicle having a substantiallywater-tight hull, a sprocket at one end of the hull, a drive motorwithin the hull for driving the sprocket, an idler at the opposite endof the hull and forming an idler'oi the track, idler wheels between andsubstantially in line withv the sprocket and end idler, means forraising the intermediate idlers with respect to the hull andsimultaneously depressing the end idler into engagement with the trackto elongate its traction base to condition the vehicle for water travel.

4. An amphibious track-laying vehicle, comprising a drive motor, tracksdriven by said motor, a substantially rectangular water-tight hullhaving a laterally projecting compartment on each side, a cylinder ineach end of each compartment, double acting pistons in said cylinder,idlers connected with said pistons below the compartments andconstituting suspension means for supporting the vehicle. on the tracks,fluid pressure means for reciprocating the pistons in said cylinders toraise and lower the suspension means relative to the vehicle body, andidlers in line with the idlers of the suspension means, a cylinder foreach of the last-mentioned idlers, each of said cylinders having apiston connected with said idlers and arranged vto move them from oneslack take-up position to another, and fluid pressure connectionsbetween the idlercylinders and the suspension means cylinders, wherebywhen the idlers oi.' the suspension means are raised, the other idlerswill be depressed to elongate 4the traction base of the tracks tocondition the vehicle for water travel.

5. In an amphibious track-laying vehicle, having a substantiallywater-tight hull, an elongatable track, a motor driven sprocket outsidethe hull and at one end thereof, and an idler at the other in line withthesprocket, reciprocable vehicle suspension means between the sprocketand the idler and adapted when extended to support the hull on saidtrack above the ground, means for reciprocating the suspension means toraise or lower the hull with respect to the track and depress the idlerwhen the hull is lowered to elongate the track and incidentally lengthenthe traction base thereof and condition the vehicle for water travel.

6. In a track-laying vehicle, a drive motor for .the vehicle, a fluidpressure pump driven by the

